Melissa Mathison, the Oscar-nominated screenwriter who wrote screenplays for filmmakers as varied as Steven Spielberg, Martin Scorsese, and Frank Oz, has passed away after a battle with neuroendocrine cancer. She was 65 years old.

Although her filmography showcases a command of several genres, she will forever be known as the woman who wrote E.T. the Extra-Terrestrial. By playing a key role in one of the most beloved films of all time, Mathison touched the lives of millions of people all over the world.

Born on June 3, 1950 in Los Angeles, California, Mathison broke into Hollywood by co-writing the screenplay for 1979’s The Black Stallion. An adaption of Walter Farley’s beloved 1941 novel of the same name, the film was a box office and critical success. However, her greatest success was wright around the corner.

Director Steven Spielberg originally set out to make an alien-centric horror movie, but Melissa Mathison’s screenplay for E.T. the Extra-Terrestrial couldn’t be more different. Sweet and smart and genuine, her story of a young boy befriending a stranded alien and helping him find a way home was one of the biggest films of the ’80s. A landmark science fiction film, a hugely influential family film, and a box office juggernaut, E.T. remains one of the best films to ever emerge from Hollywood. Mathison earned an Oscar-nomination for her work.

Mathison continued to work after E.T., but her projects were few and far between. She wrote the screenplay for The Escape Artist, contributed a segment for The Twilight Zone: The Movie, and penned the TV movie Son of the Morning Star. In the mid-’90s, she adapted The Indian in the Cupboard for director Frank Oz.

However, her next great screenplay would come in the form of Kundun, a biopic tracking the life of the Dalai Lama. One of Martin Scorsese’s most underrated films, Kundun is one of the director’s most fascinating movies and Mathison’s screenplay is a huge reason for its success. While researching the screenplay, Mathison befriended the Dalai Lama himself, which led to becoming an activist for Tibetan freedom and joining the board for the International Campaign For Tibet.

Mathison was also married to Harrison Ford from 1983 through 2004. She is survived by her two children from this marriage.

Before her death, Mathison wrote one more screenplay for Steven Spielberg. Her fourth adaptation of a beloved children’s book, The BFG is scheduled for release on July 1, 2016. In a statement released yesterday, Spielberg commented on Mathison’s passing:

“Melissa had a heart that shined with generosity and love and burned as bright as the heart she gave E.T.”

Every successful movie is the result of hundreds of people working together to build something great. But a screenplay is the blueprint that keeps everyone on the same page, the foundation upon which a masterpiece can be built. Mathison laid the foundation for one of the greatest movies ever made and directly contributed to films from master directors. Her work remains a vital component of the American film canon and she will be missed.